Table 3. Incidence outcomes by study intervention phase, overall and within the 7/14 sites included in the ’per protocol’ sensitivity analysis.
| Study phase | IRR† (95% CI, p-value) | ||||
|---|---|---|---|---|---|
| Baseline | Longer-turnaround | Rapid | Longer-turnaround vs. baseline | Rapid vs. baseline | |
| All sites | |||||
| n HOCI cases | 850 | 373 | 947 | – | – |
| n IPC-defined HAIs | 488 | 207 | 576 | – | – |
| Weekly incidence of IPC-defined HAIs per 100 inpatients, mean (median, IQR, range)* [primary outcome] | 1.0 (0.5, 0.0–1.4, 0.0–5.6) | 0.7 (0.3, 0.0–0.7, 0.0–7.6) ‡ | 0.6 (0.3, 0.0–0.8, 0.0–5.3) ‡ | 1.60 (0.85–3.01; 0.14) | 0.85 (0.48–1.50; 0.54) |
| n IPC-defined outbreak events | 129 | 33 | 114 | – | – |
| Weekly incidence of IPC-defined outbreak events per 1000 inpatients, mean (median, IQR, range)* | 2.7 (1.1, 0.0–4.1, 0.0–23.0) | 0.8 (0.0, 0.0–1.0, 0.0–8.9) ‡ | 0.7 (0.0, 0.0–0.0, 0.0–8.9) ‡ | 1.09 (0.38–3.16; 0.86) | 0.58 (0.24–1.39; 0.20) |
| n IPC + sequencing-defined outbreak events | – | 40 | 133 | – | – |
| Weekly incidence of IPC + sequencing-defined outbreak events per 1000 inpatients, mean (median, IQR, range)* | – | 1.1 (0.0, 0.0–1.5, 0.0–13.4) ‡ | 0.9 (0.0, 0.0–1.4, 0.0–7.6) ‡ | – | – |
| Sensitivity analysis | |||||
| n HOCI cases | 290 | 143 | 533 | – | – |
| n IPC-defined HAIs | 179 | 91 | 337 | – | – |
| Weekly incidence of IPC-defined HAIs per 100 inpatients, mean (median, IQR, range)* [primary outcome] | 0.3 (0.0, 0.0–0.3, 0.0–3.0) | 0.3 (0.0, 0.0–0.0, 0.0–3.4) ‡ | 0.4 (0.0, 0.0–0.3, 0.0–5.3) ‡ | 2.21 (0.82–5.92; 0.10) | 1.75 (0.75–4.08; 0.16) |
| n IPC-defined outbreak events | 58 | 14 | 55 | – | – |
| Weekly incidence of IPC-defined outbreak events per 1000 inpatients, mean (median, IQR, range)* | 1.1 (0.0, 0.0–1.3, 0.0–12.9) | 0.3 (0.0, 0.0–0.0, 0.0–5.7) ‡ | 0.4 (0.0, 0.0–0.0, 0.0–8.9) ‡ | 0.83 (0.14–4.93; 0.80) | 0.46 (0.11–1.86; 0.21) |
| n IPC + sequencing-defined outbreak events | – | 14 | 67 | – | – |
| Weekly incidence of IPC + sequencing-defined outbreak events per 1000 inpatients, mean (median, IQR, range)* | – | 0.3 (0.0, 0.0–0.0, 0.0–5.7) ‡ | 0.5 (0.0, 0.0–0.0, 0.0–7.6) ‡ | – | – |
IPC-defined HAIs are considered to be ‘probable’ or ‘definite’ HAIs.
HAI, hospital-acquired infection; HOCI, hospital-onset COVID-19 infection; IPC, infection prevention and control; IQR, interquartile range; IRR, incidence rate ratio.
*
Descriptive data over all week-long periods at all study sites.
†
Adjusted for proportion of current inpatients at site that are COVID-19 cases, community incidence rate, and calendar time (as displayed in Appendix 1—figure 5 and Appendix 1—figure 6 for all sites).
‡
Not including data from the first week of each intervention period or in the week following any break in the intervention period.